I've got Intel graphics and a 4K monitor on Linux. With the Intel drivers, I have no vsync (I can't use TearFree because of strange video corruption issues), but things mostly run correctly. With modesetting drivers, I have triangular tearing and serious performance issues in Sublime Text, but _do_ have vsync in fullscreen.

My workaround for watching movies with vsync? Use Intel drivers in my main X session, modesetting in a secondary X session just for mpv.